Glutamate is the most abundant excitatory neurotransmitter in the mammalian central nervous system. Glutamate plays a pivotal role in cognition, mood, and motor function, and its neurotransmission becomes unstable in psychiatric diseases and neurological disorder. Glutamate receptors are divided into ligand gated ion channels and G protein-coupled receptors, and the ligand gated ion channels are further divided into α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, N-methyl-D-aspartic acid (NMDA) receptors, and kainic acid (KA) receptors. (non-patent document 1)
AMPA receptor is one kind of receptor for excitatory neurotransmitter glutamate, and was named for the selective activation of the receptor by AMPA. AMPA receptors are composed of 4 subunits (GluR1, GluR2, GluR3, GluR4). Each subunit exists in flip and flop alternatively spliced variants. AMPA receptors form homo- or hetero-tetramers composed of these subunits in vivo. The physiological property of AMPA receptor has been reported to change depending on the subunit composition. (non-patent documents 1, 2, 3)
The importance of AMPA receptor in cerebrophysiology is well known, and a compound having an AMPA receptor potentiating action is expected to be useful as a prophylactic or therapeutic drug for psychiatric diseases, neurodegenerative diseases, cognitive disorders, sleep disorders and the like. (non-patent documents 4, 5)
As a heterocyclic compound, patent document 1 discloses disodium {4-(acetylamino)-8-[(3-{2-[4-(acetylamino)-2,2-dioxido-7-(sulfonatomethyl)-6H-pyrazolo[5,1-c][1,2,4]thiadiazin-8-yl]ethenyl}-5,5-dimethylcyclohex-2-en-1-yl)methylidene]-2,2-dioxido-8H-pyrazolo[5,1-c][1,2,4]thiadiazin-7-yl}methanesulfonate.
In addition, non-patent document 6 discloses 2,2,2-trichloro-N-(7,7-diphenyl-6,7-dihydro-5H-pyrrolo[2,1-c][1,2,4]thiadiazol-3-ylidene)acetamide.